1. Field of the Invention:
This invention relates to a method and apparatus for removing the tops of plants prior to harvesting and, more particularly, to apparatus which lifts the tops and positions the tops for cutting by a cutter blade.
2. Description of the Prior Art:
The method and apparatus described herein is particularly adapted to removing the tops of onion plants. An onion is a biennial herbaceous plant with long, tubulated leaves and a pithy stalk. The stalk and leaves grow upwardly from a bulbous portion which grows partially above the top of the soil. The root structure of onions comprises a multiplicity of segments growing into the soil from the lower portion of the bulb. The individual segments extend outwardly and downwardly and anchor the bulb to the soil and, of course, provide for the intake of nutrients for the onion.
Onions typically grow in beds with single or multiple rows between furrows, depending on local farming or cultural practices. In some areas, onions grow adjacent each other, without clearly defined rows, and are accordingly relatively dense in a bed.
About a week prior to harvesting the onions in some areas, the tops, or the stalk and leaf portion of the onion plants, are rolled or bent in one direction as part of the pre-harvest processing. The rolling of the tops prevents any new growth from occurring in the onion plants and helps dry out the neck of the onion. These processes are of significance with respect to the actual harvesting of the onions, and the bent tops must be considered during a mechanical "topping operation".
In other areas, rolling is not accomplished, but the tops, or some of the tops, are bent over for various reasons, such as their own weight or pressure caused by wind. Accordingly, some of the tops, even without rolling, are bent and require particular handling during the cutting or topping process.
While various types of apparatus are used to "top" various growing plants, such as sugar beets, the prior art does not include apparatus for topping onion plants. In most prior art apparatus used for topping plants, a single plant is topped by itself. The apparatus generally includes means for guiding the plant top into a pair of blades which severs the tops and the apparatus also generally includes some means for rejecting the cut tops away from the root of the plant. In such situations, the plants to be topped are generally aligned in a row singly and spaced apart. Accordingly, only a single plant is usually topped at any one time. In other situations, flails are used to hack or tear tops from plants. Regardless of the specific method or apparatus used, it is usually of little concern whether or not the edible or consumable portion of the plant, such as the root or bulb, is bruised or nicked or cut in the topping operation.
With respect to the growth of onions, the plants grow adjacent each other in relatively thick profusion along a bed, typically about twenty-four inches wide, as illustrated herein. The individual plants are shown generally adjacent each other such that the top of the bed resembles an old-time cobblestone road. That is, the bed resembles the old-time cobblestone road after the tops are removed from the plants. The bulbs generally grow partially on top of the surface, with roots extending downwardly into the ground. The tops of the plants extend upwardly and accordingly before the onions are topped, the bed or the row appears to be a tangled mess of green stalks. The stalks are relatively thick because the plants themselves are closely spaced.
In some areas, as indicated above, about a week prior to the harvesting of the onions, the onion tops are rolled in one direction. The rolling is accomplished by literally rolling over the tops of the plants just above the bulbs to knock down the tops. when the rolling of the tops has been accomplished, the bed appears to be a mass of green stalks generally aligned in a single direction. This rolling is part of the pre-harvest processing of the onion plants. The rolling prevents any new growth of the plant and helps dry out the neck of the onion prior to the harvesting. Thus, when the harvesting occurs, the onion has, as a result of rolling, ceased its growth and has started its drying out process which prevents bacteria from entering into the bulb itself.
Since the onion bulbs grow partially above the soil, any processing must be relatively gentle on the plants so as to prevent any damage, such as bruising or cutting, of the plants. Thus it is of substantial concern that the onion bulb not be harmed during the topping operation.
With the above description of the harvesting equipment comprising the prior art, and the brief outline of onion processing and harvesting, it is obvious that ordinary apparatus, such as used to remove the tops from sugar beets, carrots, and the like, would not be applicable to the removal of tops from onions. Accordingly, the apparatus of the present invention comprises apparatus which will mechanically remove the tops from plants, such as onions, without doing any harm to the bulb portion of the plant.